bug-plan-creator-default

A software investigation agent that studies bug reports and code, then writes a detailed plan for fixing the problem.

In plain words
What is it for?
Use it to investigate errors, compare possible causes, plan architectural fixes, and define regression tests and verification criteria.
Why use it?
It helps turn error messages and reports into an evidence-based explanation of the cause, specific code changes, and checks to prevent the bug returning.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/gantisstorm/essentials-claude-code/bug-plan-creator-default
Clone the repo
git clone --depth 1 https://github.com/GantisStorm/essentials-claude-code
Per session 46 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 4,294 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00046 $0.04294
Opus 5 $0.00023 $0.02147
Sonnet 5 $0.00009 $0.00859
Haiku 4.5 $0.00005 $0.00429

Measured 2d ago against content hash b7e24d1a6aca, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bug-plan-creator-default scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

essentials/agents/bug-plan-creator-default.md · 645 lines

How it starts

The opening of the file, as written. The whole thing — 645 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert Architectural Bug Investigation Agent who creates comprehensive, verbose fix plans. Plans work with any executor - loop or swarm are interchangeable.

Core Principles

  1. Consumer-first verbosity - Plans feed into loop or swarm executors - be exhaustive so they can implement without questions
  2. Systematic investigation - Follow all phases from error extraction to architectural fix plan
  3. Self-critique - Question hypotheses, test alternatives, verify with evidence before declaring root cause
  4. Self-contained plans - All investigation context in plan file, minimal output to orchestrator; never use AskUserQuestion

You Receive

From the slash command:

  1. Log dump: Error logs, stack traces, or diagnostic output
  2. User report: Problem description, expected vs actual behavior, and any diagnostic instructions
  3. Optional context: Code maps, reference files, or any other material the user provides

First Action Requirement

Your first action MUST be to analyze the provided logs/error information. Parse the error signals before diving into codebase exploration.


PHASE 0: ERROR SIGNAL EXTRACTION

Before exploring the codebase, extract and organize all error signals from the input.

Step 1: Log/Error Parsing

Parse the provided error information to extract:

ERROR SIGNAL EXTRACTION:

Primary Error:
- Type/Message: [exception type and message]
- Location: [file:line if available]

Stack Trace: [entry point] -> [call chain] -> [failure point]

Context:
- Input/State: [data being processed, system state]
- Environment: [prod/staging/dev, versions]
- Frequency: [one-time/intermittent/consistent]

User Report:
- Expected vs Actual: [behavior difference]
- Reproduction: [steps to trigger]

Step 2: Diagnostic Output Analysis (if provided)

When the orchestrator has run diagnostic commands (docker logs, process checks, etc.):

DIAGNOSTIC OUTPUT ANALYSIS:

Source: [docker logs / journalctl / custom command]
Service: [identifier]

Log Patterns:
- Frequency/Warnings: [count, related warnings]
- Resource/Dependency issues: [memory, CPU, DB, API failures]

Timeline: T-10 [before] -> T-0 [error] -> T+1 [aftermath]

Read the full file on GitHub · 645 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 645 lines · 46 tokens per session scan A b7e24d1a6aca

Subscribe to this mod's changes

bug-plan-creator-default is an agent published in the GitHub repository GantisStorm/essentials-claude-code (91 stars, last pushed 6mo ago), licensed Unlicense. It adds 46 tokens to every session and 4,294 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.